This invention relates generally to magnetic shielding and more particularly, to systems and methods for passive magnetic shielding.
A magnetic field generator for Magnetic Resonance Imaging (MRI), hereinafter referred to as a magnet, having a strength of 1 Tesla (T) or higher generates a fringing magnetic fields beyond the physical dimensions of the magnet itself.
Such magnetic fields are potentially dangerous and may have adverse effects on people who are within a proximity of such a magnet. As a result, it is generally considered desirable to limit or curtail the fringing magnetic fields of such magnets in an MRI system of a relocatable unit, such as a mobile van or a relocatable building. It is generally considered desirable to curtail the fringing magnetic fields below approximately five Gauss beyond a certain distance, for example, 15 centimeters, from the outside side-wall of the mobile MRI unit carrying the magnet.
The mobile MRI unit used to carry the magnet in sensitive environments includes shields that shield the fringing magnetic fields generated by the magnet to satisfy the limit. However, if a higher strength magnet, having a value of, for example, 3 T, is used, the shields may not be effective for the fringing magnetic fields generated by the higher strength magnet to meet the limits using conventional methods while satisfying the weight limitations for the mobile MRI unit set by the department of transportation or any other governing body